On the ability of RCMs to capture the circulation pattern of Etesians

The Etesians are among the most persistent regional scale wind systems in the lower troposphere that prevail over the eastern Mediterranean during the extended summer season. The performance of five high-resolution EURO-CORDEX regional climate models (RCMs) in simulating the Etesian climatology as well as the associated large-scale atmospheric circulation is investigated. The model outputs are validated against reanalysis datasets (ERA-Interim, 20CR-v2c and ERA20-C) and daily station observations covering the period May to September 1989-2004. Results show that most RCMs coherently reproduce the number of observed Etesian days, the duration of their episodes and the wind field over the Aegean Sea. The majority of RCMs better reproduce in situ wind speed than the driving model, especially over the central and southwestern Aegean Sea. All models represent very well the mean state of the large-scale atmospheric circulation associated with Etesians both at the surface and at mid to upper troposphere, compared to reanalyses. Statistically significant differences vary depending on the subperiod, generally with a better performance for September. The performance of the models improves significantly with decreasing pressure gradient over the Aegean. Finally, results highlight the ability of EURO-CORDEX RCMs in simulating the Etesians over the Aegean, especially the DMI, SMHI and IPSL, which makes them efficient tools for wind energy applications.